HD4048212RFS datasheet(39/149 Pages) RENESAS

39 / 149 page

HD404829R Series

Stop Mode Cancellation by

STOPC : The MCU enters active mode from stop mode by inputting

STOPC as well as by RESET. In either case, the MCU starts instruction execution from the starting

address (address 0) of the program. However, the value of the RAM enable flag (RAME: $021, bit 3)

differs between cancellation by

STOPC and by RESET. When stop mode is cancelled by RESET, RAME

= 0; when cancelled by

STOPC, RAME = 1. RESET can cancel all modes, but STOPC is valid only in

stop mode;

STOPC input is ignored in other modes. Therefore, when the program requires to confirm that

stop mode has been cancelled by

STOPC (for example, when the RAM contents before entering stop mode

is used after transition to active mode), execute the TEST instruction to the RAM enable flag (RAME) at

the beginning of the program.

MCU Operation Sequence: The MCU operates in the sequence shown in figures 20 to 22. It is reset by

an asynchronous RESET input, regardless of its status.

The low-power mode operation sequence is shown in figure 22. With the IE flag cleared and an interrupt

flag set together with its interrupt mask cleared, if a STOP/SBY instruction is executed, the instruction is

cancelled (regarded as an NOP) and the following instruction is executed. Before executing a STOP/SBY

instruction, make sure all interrupt flags are cleared or all interrupts are masked.

Power on

RESET = 1 ?

RAME = 0

Reset MCU

MCU

operation

cycle

Yes

Figure 20 MCU Operating Sequence (Power On)

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